Combination frequency selector



April 8, 1958 E. P. THIAS COMBINATION FREQUENCY SELECTOR e sneets-shee't1 Filed Dec. 17. 1953 April 8, 1958 E. P. 'rl-HAS 2,839,182

COMBINATION FREQUENCY SELECTOR Filed Dec. 17. 1955 6 Sheets-Sheet 2 1NVEN TOR. oa//N P. Tel/4s Affinia/#Vs April 8, 1958 E. P. 'rl-UASCOMBINATION FREQUENCY SELECTOR 6 Sheets-Sheet Filed Dec. 17. 1953 lumINIHNJI g INVENTOR. fard/v E ffl/4s BYQJ Wye/iw) April '8, 1958 E. P.THlAs I COMBINATION FREQUENCY. SELECTOR 6 Sheets-Sheet 4 Filed Deo. 17.1955 April 8, 1958r E. P. THlAs 2,830,182

COMBINATION FREQUENCY SELECTOR 6 SheeCs-Sheerl 5 Filed Deo. 1'7. 1953April 8, 1958 E. P. THlAs COMBINATION FREQUENCY SELECTOR 6 Sheets-Sheet6 Filed DSG. 17. 1953 Trae/vins* United States Patent f' COMBINATIONFREQUENCY SELECTOR Edwin P. Thias, Los Angeles, Calif., assignor'toStandard Coil Products Co., Inc., Los Angeles, Calif., a corporation ofIllinois Application December` 17, 1953, Serial No. 398,772

8 Claims. (Cl. Z50- 40) My present invention relates to televisiontuners and more particularly it relates to discrete type tuners operablein the V. H. F. and U. H. F. ranges.

In co-pending application Serial No. 325,514, filed December 12, 1952,now Patent No. 2,773,986, a discrete type tuner was disclosed comprisingtwo turrets mounted on concentric shafts of which one selected U. H. F.channels, the other V. H. F. channels. A switch was provided -so thatduring U. H. F. reception, the V. H. F. section of the tuner would bedisconnected from the V. H. F. tuning elements connected to anothergroup of tuning elements and would perform as an amplifier. When a V. H.F. channel was desired, this switch provided a connection between thetuning elements of the V. H F. section and stationary mounted elementsof the V. H. F. section.

In order to select a channel within a given band, U. H. F. or V. H. F.,it was rst necessary to switch in the desired band and then by operationof a second control the individual channel within that band wasselected. In addition, tine tuning means were provided in both the U. H.F. and V. H. F. section to tine tune after discrete selection of thedesired channel.

In other words, the switch contacts must be capable of providing goodelectrical connections at two different points, one point correspondingto the connection with the V. H. F. turret, the other pointcorresponding to the connection with the auxiliary circuit.

The position of the previously mentioned switch was determined by the U.H. F. turret so that in one position of the U. H. F. turret the switchwould take a certain position while in all the other positions of the U.H. F. turret, the switch would take a second position.

The control mechanism of the switch mechanism consists in the presentinvention of a cam surface forming an integral part with the U. H. F.turret engaging a cam follower having a shaft positioned so that it canoperate the switch to either of its two positions. The cam following andthe shaft are appropriately biased against the cam surface, and the camsurface in this particular embodiment has a number of similar notchesand f two dissimilar notches. One of the dissimilar notches causes thecam follower and, therefore, the switch structure to take the positioncorresponding to V. H. F. reception under all conditions. The otherdissimilar notch through operation of a sliding member may cause the camfollower and therefore the switch structure to take the position foreither V. H. F. or U. H. F. reception.

It may be necessary at this point to recall the fact that there are 12V. H. F. channels numbered 2 to 13, inclusive, in addition to the U. H.F. channels 14 to 84. The l2 V. H. F. channels occupy a frequency rangeextending from 54 megacycles (channel 2) to 216 megacycles (channel 13).The U. H. F. channels instead occupy a frequency range from 470 to 890megacycles.

If then 1) a desired system of tuning is used, that is one in which thetelevision frequency range is divided ICC ` in bands of I channels each,for example, band 3 comi prises channels 30-39, and (2) if the U. H. F.and

V. H. F. tuning means are different and separate but the same channelpositioning means are used for both V. H. F. and U. H. F. channels, and(3) in view of the fact that thereY are 12 V. H. F. channels, the cammechanism for operating this switch must be such that it will bepossible to tune from V. H. F. channel 13 to U. H. F. channel 14 bycontinuous rotation of one member without having to operate othercontrol means for selection of the U. H. F. or V. H. F. ranges.

The complete turret assembly consisting of a U. H. F.

and a V. H. F. turret and their shafts is mounted in the tuner chassiswhich is essentially divided also in two sections, the U. H. F. sectionand the V. H. F. section separated appropriately by a shield.

The chassis is provided at its two end walls with pockets obtainedthrough `stamping of the metallic chassis so that a simple spring clipwithont any hooks can be used to engage the two ends ofthe operatingshafts and the above mentioned pockets of the chassis to securely mountthe turret assembly against movement of the turret assembly away fromVthe chassis. That such a movement away from the chassis may be possiblewithout the use of these spring clips is`obvious when it is consideredthat in the present tuner two detent discs are used requiring, there-YLfore, two spring members provided with rollers biased against thenotches of thepositioning discs. In addition,

the stationary contact structures will also tend to bias the turretsaway from the chassis.

In addition to the turret structures, the present tuner is providedwith,.as previously mentioned, fine tuning means,

one for ne tuning in U. H. F. channels, the other for tine tuning in V.H. F. channels.

The finev tuners'are essentially capacitors, the capacitance variationof which is obtained by moving a dielectric plate with respect to thetwo conductive plates of the capacitor assembly. The two dielectricplates are mounted on a single shaft and operated by rotation of asleeve concentric with the shafts of the turrets.

The U. H. F. panels described above are mounted on sitioning purposeswhen engaged by an appropriate detent mechanism.

The extension of the U. H. F. panels is provided with shoulders ,suchthat a spring member mounted on the outside of this turret on the seconddisc and having a circumferentially bent portion engages the shouldersof the extension of the U. H. F. panels so that the bent portion` ofthis spring biases these panels against the second disc.

Removal of the panels from the turret can then be obtained by movingthepanel away from the turret in they.

radial direction, overcoming the position presented by the disc mountedspring member.

Such positioning means are particularly necessary atr ultra-highfrequencies Where it is well-known any slight displacement with respectto a preselected position of the panels may cause detuning andconsequent loss of picture.

The positioning of the oscillator tube of the U. H. F.

Asection is at an angle with respect to the vertical direction so as topermit not only the mounting of the tuner near the cathode ray tube butalso adjustment of elements i mounted on the same side of the tuner onwhich the tubes are mounted. Y

V'Ihe foregoing and many other objects of the inveni Patented Apr. 8,1958 tion will become apparent in the following description and drawingsin which:

Figure 1 is a circuit diagram ofthe tuner of the present invention.`

Figure 2 is an exploded view ofthe tuner of the present inventionshowing the chassis of the tuner and the elements mountedon the chassisand the V. H. F.-

U. H. F. turrets.

VFigure 2a is a side view` of the tuner of the present invention showingthe positioning means and the tine tuning mechanism.

Figure3 is a top View of the tuner of the present invention showing theU. H. F..crystal mounting means and the U. H. F. and V. H. F. inputsrj iFigure 4 is a detail View of the terminal of the V. H. F. sectionconnections taken along line 4-4 of Figure 3 looking in the direction`of thc` arrows.

Figure 5 is a top .view of a detail of the tunerof th present inventionshowing the U. H. F. input ltering means and the crystal mounting means.In this gure the upper part of the U. H. F. chassis has been removed.

Figure 6 is a detail view of the crystal mounting means and crystal ofthe U. H. F. tuner taken at line 6--6 of Figure 3 looking in thedirection of the arrows..

Figure 7 is a side view of the U. H. F. turret with all the U. H. F.panels removed except one.

Figure 8 is a top view of one embodiment of the U. H. F. panels.

Figure 9 is a bottom view of the panels of Figure 8.

Figure 10 is a side view of thepanels of Figure 8.

Figure 11 is another side view of the panels of Fig- Y ure 8.

Figure 12 is the rear view of the U. H. F. turret. Figure 13 is thefront view of the U. turret showing one .U. H. F. panel mounted, thepanels biasing spring member and the adjusting screws.

Figure 14 is a front view of the spring member used in the supportingdisc of Figure 13.

vFigure 15 is a cross sectional view taken at line 15--15 of Figure 14of the spring member of the supporting disc shown` in Figure `13.

Y Figure 16 is a cross-sectional view taken at line 16-16 of Figure 2alooking in the direction of the arrows and showing the cam carryingportion of the U. H. F. turret.

4Figure 17 is an assembly drawing taken at line 17-17 of Figure 16lookingin the direction of the arrows.

Figure 18 is a detail `view of the cam supporting disc of the U. H. F.turret.

Figure 19 is another view ofA the disc of Figure 18.

Figure 20 is a cross sectional view taken at line 20--20 of Figure 19looking in the direction of the arrows.

Figure 21 is a detail view of the movable member of the cam mechanism.of the present invention.

Figure 22 is a cross-sectional view taken at line 22-22 of Figure 21looking in the direction of the arrows.

ReferringV rst to Figure l showing the schematic circuit diagram of thepresent U; H. F.V. H. F. tuner, the V. H. F. antenna 50 which isr shownhere as a balanced antenna is connected to a series circuit consistingof a capacitance 51 and a variable inductance 52. Variable inductance 52may consist of a coil with a conductive slug within it so thatdisplacement of the slug with respect to the coil produces the desiredvariation in inductance. Across the balanced output of this coilassembly is placed a balanced center tapped coil (iron core) 55.

To be more specific, section 50a of V. H. F. antenna 50 is connected tothe free end ofinductance 52 while the other side, 50h, of antenna 50 isconnected to the free end of capacitor 51. Y

.Antenna section 50a ris also connected to a parallel c1rcu1t consistingof an inductance 53 and a capacitance 54. The other side of the parallelcircuit 53.--54 is connected toV a fixed terminal B. Similarly, section50i:

of antenna 50 is connected to the parallel circuit consisting ofinductance 56 and capacitance 57. This parallel circuit is connected onthe other side to a stationary contact A.

It should be noted that aside from the antenna 50 andthe transmissionline from the antenna to the series circuit 51--52,` the othercomponents described above are xedly mounted on the chassis of the tuneras show hereinafter in connection with Figures 2 and 3.

When the tuner isset for V. H. F. reception, that is, for reception onan individual V. H. F. channel, an antennasegment 68 mounted on the V.H.. F. turret also described hereinafter is connected to the fixedterminals A and B and the other fixed terminals C, D, E on the inputside of the V. H. F. tuner.

Contact C is a `xed contact connected to ground. Contact E is connectedto the grid 61 of grounded cathode triode 62. Contact D is connected toground through by-passing capacitor 64.

Mounted on panel 60 is an input transformer having its primary side 65balanced to ground through connection of its two ends to stationarycontacts A and B respectively by means of appropriate movable contacts66 and 67 mounted on panel 60. i

Primary coil 65 is center tapped and the center tap is connected to amovable Contact 69 which in turn engages contact C, thus grounding thecenter tap of coil 65. Also mounted on panel 60 is a secondary 68 oftransformer 65-68. Secondary 68 has its terminals connected to movablecontacts 70 and 71, which engage the stationary contacts E and Drespectively.

It will now be apparent that the transformer 65-68 `mounted on panel 60serves not only as an input coupling xsignal which appears acrossstationary contacts E and D is supplied to the grid 61 of groundedcathode triode 62 of R. F. amplier 75. P.. F. amplifier 75 consists oftwo triodes 62 and 76 connected in cascode.

To be more specific, stationary contact E is connected not only to grid61 of tube 62, but also through a series circuit consisting ofresistances 78 and 79 to a terminal 80 towhich, as noted in Figure i, anA. G.-C. voltage may be applied as a bias.

A capacitance 81 connected between resistance 79 and contact 80 servesto by-pass to ground A. C. signals which would otherwise causefluctuations and therefore distortion in the output of triode 62.Cathode 82 of triode 62, as previously mentioned, is grounded whileplate 83 of 'tube' 62 is connected on one side to a series capacitance84and to contact D.

lnparallel to the previously mentioned capacitance 64 yis also a trimmercapacitor 85. On the other side, plate 83 of tube 62 is connected tocathode 90 of grounded grid triode 76 through a series inductance 91.Cathode is connected to ground through capacitance 92 in series with asecond capacitance 93. Grid of triode 76 is grounded through resistance96 connected between grid 95 and ground and is connected to the.v commonpoint between capacitances 92 yand 93 through series resistances 98 and99. The common point between rcsistances 98 and 99 is connected throughconductor 100 to a stationary contact 101 to which, during operation ofthe tuner, a B-l-z supply is connected.

To ensure proper operation of the R. F. amplifier, lead 103 betweenresistance 96 in grid 95 is by-passed to ground by means of afeed-through capacitor 1115 and lead is `by-passed to ground through afeed-through capacitor 106. i

Finally, plate of triode 76 is connected to a trimmer capacitor 111connected between plate 110 and ground and to a stationary' contact F.The common point between capacitances 92 and 93 and resistance 99, isconnected to another` stationary contact G.

` During operation of the tuner, a second panel 115 is inductances 116,117 and 118.

which engage respectively stationary contacts F and G. 1nductance 117terminates at panel mounted contacts 122 and 123 which engage stationarycontacts K'fand H. Finally, inductance 11S terminates at movablecontacts 124, 125 which engage stationary contacts L, and M`respectively.

While inductance 116 and Vinductance 117 are fixed inductances,inductance 113 is variable and generally of a slug tuned type. Sinceinductances 116, 117 and 118 are mounted in the same panel 115 and arenot shielded from each other, there will be mutual coupling between thethree inductances so that a signal appearing, for example, acrossinductance 116 would be coupled to inductance v117,V and a signalappearing across inductance 11S would also be coupled to'inductance 117.

1nductance 117 which is connected to stationary contacts K-and H, is inthe input yof converter tube, in this case a pentode 127, through acoupling capacitor 128' connected between contact K and grid 129 ofpentode 127. Contact K is connected to ground through resistance-130 andgrid 129 is connected to ground through the'series fore designated as T.P'. in Figure l.

Across the resistance combination 131 and 132 is connected a trimmercapacitor 133. Cathode 134 of converter 127 is connected to ground andto suppressor grid- 135. Screen grid 136 of tube 127 is connectedthrough a dropping resistance 138 to plate 139 of tube 127`and isby-passed to ground by capacitor 140 connected between screenY grid 136and ground.

The output from converterv tube 127 is obtained V combination ofresistances 131 and 132. Aterminal` is brought out from the commonpointv of resistances' 131-and 152 to permit testing, of the tunerand-is there-p.

through a circuit consisting of a variable inductance 141 Y and acapacitance 142 connected in series between plate 139 of tube 127 andground. The I. F. output of the present tuner is actually obtained fromacross capacitor 142 and is brought out to a receptacle mounted on thechassis of the tuner. The common point between elements 141 and 142 isconnected to lead 100 and therefore to the B+2 supply through a droppingresistance 144.

Oscillator coil 118 is connected on one side through contact L to plate145 of oscillator triode 146. The other side of inductance 118 isconnected to the grid 147 of tube 146 through a coupling capacitor 14Sand a grid leak resistance 149. Capacitor 148 is connected betweencontact M and grid 1417 while grid leal: resistor` 149 is connectedbetween ground and grid 147.

Also connected between ground and grid 147 is capacitor 150. While afine tuning capacitor 152 ,is connected between stationary, contact Mand ground, another trimmer capacitor 155 connects contact L to ground.Also connected to ground Yis cathode 156 of oscillator tube y146.Contact M is connected to the B-l-1 supply through a resistor 158, lead159, terminal 160. Lead 159i isiproperly oy-passed to ground by means offeed through capacitor 161.

Also connected to lead 159 is a resistance 163 connected on the otherside to a contact M' of the auxiliary assembly 170'. Resistor 163 isalso connected to a receptacle Y 171 mounted on the chassis of thepresent tuner. To another contactof the same receptacle is connectedone` side lof filament 172 for the double triode tube 6276. The-otherside of filament 172 is grounded. Theungrounded side of filament 172 isconnected to filament 174 of tube 127-146 through a R. F. choke 175.Filament 174 is thus connected on one side to and on the other side toground.

A capacitance 176 is also connected to the ungrounded side of filament174 to by-pass high frequencies. The common' point between filament172ar1d` choke 175 is choke 175 connected to a lead 178 which terminatesat acontact': 179 to which, during the operation of the tuner, afilamentisupply would be supplied. Lead 178 is also by-passed to.

ground through a feed through capacitor 18,0.V

It should be apparent later, when describing the actual," configurationof the V. H. F. tuner, that feed through= capacitors 106, 161 and 180are mounted through a shield 182 which is shown schematically in Figure1.

1t is now possible to describe the operation ,of` this4 When, for exe.;ample, channel 2 is desired, then the appropriate channelV boards 6? and115 are connected to the stationary con-- V. H. F. section of thepresent tuner.

tacts A, B,'C, D, E, F, G, H, K, L, and M so that the elements mountedon panels 60 and 115 are those which correspond to the frequencies ofchannel 2 (S4-60'j mo).

The signalV of the correct frequency which appearsvon antenna 50 `mixedwith other undesired signals is ,selectedV by the input circuit of theR. F. amplifier 75. It will; appear properly amplilied at the output ofthis amplifier,1

namely across inductance 116.

At the same time, j oscillator tube 146 produces sig-'- nals of thecorrect frequency across inductance 118. c,

The input signals and the oscillator signals are coupled into the inputinductance 117 of converter tube 127 and mixed at converter 127 in amanner well known in the art so that across capacitance 142 will appearthe desired:

signal at the desired I. F., at either 2l mc. or at 41 mc. depending onwhich I. F. is used in the television receiver itself.

after when theU. H. F. operation of the present tuner will be described.i

Contacts A' and B' of assembly 70 are open and'contact C is connected tothe female of an I. F. coaxial vconnector 185 through a coil 186. Acrosscontacts E' and D' -is a coil 187 having a variable inductance. Coils186 and 187 form an I. F. transformer of which coil 186 is a primary and137 is a tunable secondary.

Connected across contact G' and F is also a variable 1nductance 190 andacross contacts H' and K' is connected a parallel circuit consisting ofa variable inductance 191 in parallel with resistance 192. Contact L' 1sleft open and contact M as previously mentioned is connected toresistance 163.

The U. H. F. section of the present tuner consists of `antenna terminals200 and 201 mounted externally on the chassis of the present tuner. Forproper operation of the present turner, a U. H. F. antenna 202 balancedwith respect to ground, is connected to terminals 200 and '201 Q througha balanced transmission line 203. Connected -to terminal 201 is acapacitance 205 having the other side connected to a grounding plate206. Terminal 200 isn connected to a capacitance 207 in serieswithanother a trimmer capacitance 212.

All the elements in the input to the U. H. F. tunerdescribed up to nowform a filtering circuit to essentially 'Y pass only U. H.v F. signalsand discriminate against Another stationary contact P is con- V. H. F.signals. nected to grounding member 206 and in alignment with contacts Nand P is a third contact Q connected to groundV through trimmercapacitor 213. Connected across contacts Pand Q is an inductance 214 andconnectedracross N and Q is a R. F. coupling capacitor 215 providingajj' constant band width for all the U. H. F. bands.

In addition to contact M', also contacts A', B', C', D', E', F', G', H',K', and L are mounted on auxiliary I assembly 170. The function of thecircuits mounted; on this auxiliary assembly will be apparent herein- .A

Whenshe Apresenti tuner is operated as a U. j;

tuner, a' panel 220 is connected `to contacts N, 'P, Q, `R, S. Panel 220carries tuning elements and `more precisely it carries a plate 221 of a`capacitor 222 where plate 221 is connected to a movable contact 223through a coil 224. The other plate 225 of capacitor 222 is connected tocontact 226.

Another plate 228 is connected to contact 229'through coil 230. Plate228 forms with previously mentioned plate 22,5 a second capacitor 231.Also mounted on panel 220.is a third capacitor 232 having one of itsplates 233 connected to a coil 234 and thence to a contact 235. Thesecondplate 236 of capacitor 232 is connected to contact 237 throughcoil 238.

A lead 240 having probes 241 at its two ends serves asy the injectingdevice between l.coil 234 `and coil 230 for injecting an oscillatorsignal into a crystal mixer as described hereafter. n

During operation of the U. H. F. tuner, plate 221 is connected throughcoil 224, contacts 223 and N, to the input lter of the U. H. F. tuner.Plate 225 is connected to ground through contacts 226, P and plate 228is connected to crystal mixer 239 through coil 230, contacts 229 and Q.

One side of crystal 239 is connected to an extension yof the ungroundedplate of capacitor 213. The other side of crystal 239 is connected tocoaxial cable 242 through feedthrough capacitor 245. Feed-throughcapacitor 245 is provided at the crystal end with a receiving membercup-shaped for receiving one terminal 243 of crystal 239. Plate 233 ofcapacitor 232 is connected tothe stationary contact R through coil 234and movv able contact 235 while plate 236 is connected to contact Sthrough coil 238 and movable contact 277. Sta-v tionary contact R isconnected to plate 247 of U. H.V F. oscillator tube 248. Plate 247 isconnected to power plug 249 through dropping resistance 250 andfeedthrough capacitor 251. Plate 247 is also connected to plate 252 of acapacitor assembly 253 which has its other plate 254 connected tocontact S and grid 255 of tube 248 and a center conductive member 256connected to ground and movable with respect to plates 252 and 254 to`vary the capacitance between plates 252 and 254 and conductive elements256.

Grid`255 is connected to ground through agrid leak resistor 258 whilecathode 259 of tube 248 is connected to ground through coil 260.

Filament 261 of tube 248 is connected on one side l to coil 262 andthence to ground and on the other side to coil 263 feed throughcapacitor 264 and onecontact of power plug 249. Connected acrossfilament 261 is also a `capacitor 265. Feed-through capacitors 251 and264 are mounted through a grounded shield shown in Figure 1 at 265 whilefeed through capacitor 245 is mounted I through'a vertical wall ofbracket 422.

Panel 220 is mounted together with similar panels to form the U. H. F.turret. This turret is operated by a shaft or a sleeve depending onmechanical details and concentric with this shaft or sleeve, as will be.seen hercinafter, is another controlling member carrying a series of`dielectric plates, namely plates 267, 268 and 269, where plate 267serves to vary the capacitance of capacitor 222, plate 268 varies thecapacitance of capacitor 231, and plate 269 varies the capacitance ofcapacitor 232.

In addition, a third controlling member serves to move anotherdielectric plate 270 to vary by small amounts the capacitance ofcapacitor 232. Y

It should be notedthat in the present invention, each panel 220 is usedto pass and select a U. H. F. range encompassing ten U. H. F; channels.

Itis now possible to describe the operation of the U. H. F. section ofthe present tuner. U. H. F. signalsJ picked up by antenna 202vpassthrough the vinput tilter described Aabove and a particular U. H. F.channel is se- "8 lected through. the 'appropriate panel 220 and theappropriate positioning of plates 267 and 268.

This incoming U. H. F. signal is then applied to the input of crystalmixer 239. At the same time, dielectric plates 269 and 270 may beproperly positioned with respect to plates 233 and 236 of capacitor232so as to cause oscillator 248 to geneate the desired frequency signal.This signal is injected by means of injection device 240 into coil 230and thence again into the input of crystal mixer 239.

When the frequency of oscillation of oscillator 248 and the frequency ofthe U. H. F. signal mix in crystal mixer 239, an output is obtainedhaving the desired intermediate frequency of 2l or 45 me. depending onthe intermedlate frequency of the television set itself. In the present1nvention, during U. H. F. reception, the cascode amplifier 75 and theconverter 127 of the V. H. F. section are utilized as intermediatefrequency amplifiers while the V. H. F. oscillator is made inoperative.

During U. H. F. reception, in fact contacts A-B-C-D- E-F-G-H-K-L-M aredisconnected by means of a switching device from the contacts mounted onthe V. H. F. turret and are caused to engage contacts AB'CDE'FGHKL'Mrespectively of assembly 170.

lWhenthis connection is made, as can be clearly seen in lbeing mutuallycoupled to coil 186 will have across the terminals E and D` andtherefore across its contacts E and D, the I. F. signal which is thenapplied to cascod'e amplifier 75 now operating as an I. F. amplifier,`that is a xed frequency amplifier. The output of eascode ampliiier 75appears across a coil 190 through engagement of its terminals F and Gwith stationary contacts F and G.

The signal across the inductive load is applied through lseries network193-194 to the input circuit 19t-192 having its terminals H and K nowconnected to contacts H and K of the input of'tube 127. Tube 127 nowoperates as another I. F. amplier so that across capacitor 142 will nowappear an I. F. signal containing the information existing in theoriginal U. H. F. signal.

The signal appearing across capacitor 142 has now been considerablyamplified by .the cascode amplier 75 and amplifier tube 127.

f Since now no circuit element is connected between contacts L and M andcontact M is connected to contact M to short circuit resistances 158 and163, oscillator tube 146 is made for all practical purposes inoperativeso that it cannot produce interference or noise signals. Resistance 163serves to keep alive the voltage to the U. H. F. oscillator tube 248when the tuner is in V. H. F position.

It should be noted that whether operating as a V. H. F. or U. H. F.tuner plug 249 and receptacle 171 are always properly connected togetherby means of conductors (not shown) in a manner well known in the art.

i A side cut away view of the tuner of the present inven tion is shownin Figure 2. The V. H. F turret 300 is seen to consist of antennasegments 60 and oscillator segments or panels 115. The panels aremounted to form turret 300 on three supporting discs, 298, 299 and 301.The two lateral ones 298 and 299 and the center one 301 are providedwith appropriate notches such as 302 engageable by roller 303 carried bya spring member 304 secured to the metallic chassis 305 and extendingthrough an opening 308 of member 304. For greater details on theconstruction of the V. H. F. turret reference is made to Patent No.2,496,183 to Thias.

The three vsupporting discs for turret 300 areV secured to a shaft 310(see Figure 2a) extending through the whole length of the tuner and moreparticularly extending beyond the end wall 312 of chassis 305 inV-shaped opening 313 at its end 315. V-shaped opening 315 is engaged bya reentrant portion (not shown) of shaft 310 so that the V-shapedportion of end wall 312 acts as a bearing for shaft 310.

End wall 312 is stamped so that two pockets 316 and 317 are obtained oneach side of opening 313. Simple wire spring 318 is used to bias shaft310 against the V-shaped opening 315 so that shaft 310 may not move awayfrom its V-shaped bearing 315. Wire spring 318 engages at its ends theopenings provided by pockets 316 and 317 and engages centrally thelabove-mentioned end of shaft 310.

The co-axial terminal 185 is mounted on the upper surface of chassis 305and in Figure 2 coaxial terminal 185 is shown in engagement with thecoaxial cable 242.

Also mounted on the upper surface of chassis 305is the V. H. F. in putcircuit described in connection with Figure 1 of which only terminals320 and 321 are visible in Figure 2. To terminals 320 and 321 areconnected during its use the two conductors of a balanced transmissionline originating from V. H. F. antenna 50 as is well-known in the art.

Similarly mounted on the upper surface of chassis 305 are the cascodeamplier tube 75and the oscillator converter tube 127-146. Also visibleon the upper surface 305 are trimmer capacitors described in connectionwith the V. H. F. section of Figure 1. Fixedly mounted on a plasticmember 325 and secured in the interior of the upper surface of chassis305 are the stationary contacts A-B-C-D-E-F-G-H-K-L-M.

These contacts are riveted at 326 to the plastic insulating support 325.Contacts A to E' engage, during V. H. F. operation, movable contacts 66,67, 69, 71 and 70 respectively of panel 60.

It is also found that providing a centrally located ground contact 69and by separating the two coils so that one is mounted close to theother but not over the other, it is found that the capacity to thesecondary is greatly reduced. It can also be said that the position ofthe grounding contact 69 between the two coils of the input transformer65-68, which are reverse helices, reduces stray capacity. Stationarycontacts F to M engage during V. H. F. operation the turret mountedcontacts 1Z0- 121-123-122-124 and 125 respectively as shown also inFigure l.

Referring again to Figure 2, the U. H. F. turret 340 is formed by aseries of panels 220 supported and mounted on end discs 341 and 342 (seealso Figures 12, 13, 16, 17 and 19). Disc 341 is provided with a numberof slots 344 rectangularly shaped to be engaged by an extension 345 ofpanels 220. In addition to having a number of slots 344 equal to thenumber of panels to be mounted on supporting disc 341, disc 341 has whatmay be called a V. F. position shown in Figure 13 at the V-shaped notch346. Slightly to one side of notch 346 is an opening 347 also in disc341 which,.as seen hereinafter, permits adjustment of the V. H. F.oscillatorcoilsfrom the frontend of the tuner during V. H. F. reception.End

plate 341 is metallic and thus serves alsolas theA ground plate. for theadjusting screws 348 for the oscillator capacitor 232. v

It may be seen, in fact, in Figure v7 that adjusting screws 348 afterengaging conductive discs 341 extend close to plate 236 of oscillatorcapacitor 232 so that Vthe position of adjusting screw 348 with respectvto 'that of plate 236 `will determine the amount ofY capacitance tothrough appropriate. threaded .openings-g andarqlheldyvagainstv.undesired movement by Wire springs 350- andv 351 appropriately bearingagainst .the threads of adjustingscrews 348. Riveted on the externalpart of disc 341,isy a spring disc 353 shownin detail in Figures 14 and15., Disc 353 is provided'with 4openings 354 .which are similar toopenings 354 in disc 341 with the addition of afv circular portion 355which serves to permit screws 348 to go through spring discs `353 vandengage conductive disc 351. .Spring disc 353 is also provided with alargerV opening 357 corresponding with notch 346 of disc 341.

Spring disc 353 as seen more clearly in Figure 15 is flatat the centerportion 356 and is raised at 358 to form ar. Vshaped circular band.Spring disc 353 is secured to disc 341 in any known way, for example, bymeans of rivets.

Both spring member 353 and discv341 are provided f with `anappropriately centrally. positioned opening topermit their mounting on ashaft 359 (see Figures 2 and 7) `which is kactually a sleeve throughwhich V. H. F. shaft 310extends so as to permit control of the V. H. F.turre't,

300 from the front end of the television tuner.

In the Iback of disc 341 on each Iside of each opening 344 are smallstamped out retaining elements 360 which,

as described hereinafter, serve to retain panels 220after mounting frommoving in the radial direction. The 'back plate 342 consists 'of a discprovided with pairs of Y radially *extending fingers 365. Fingers 365are provided;

with an enlarged end or head 366 so that after each pair of lingers 365is made to pass through slot 378 of panels 220, heads366 will preventmotion of panel 220 Vavv-ay y from disc 342 or will prevent radialmotion of panels 220.v

Disc 342 (Figure 12) is further provided with a cenf trally positionedcam surface 368 (see also Figure 16).

Cam vsurface 368 is broken for a certain length to permit' the insertionof a radially moving piece 369 having also notches such as 370 similarto notches 371 of cam surface 368. Member 369 can move radially since itis prov.V

vided (see Figures 21 and 22) with longitudinal slot 373 which engagesshaft 310 of the V. H. F. turret 300.

Member 369 is also provided with a raised portion 374.*-

Member 369 is, therefore, so shaped that when sector 375.

mounted on V; H. F. shaft310 moves with respect to.. disc 342, it willengage for a certain angular range the shield or raised portion374 ofmember 369 so as to move member 369 in the radial outer direction.

when Sector 375 does not engage shoulder 374 of member 369, ap-

propriate spring means described hereinafter serve to return member 369to a lower position as determined by the ilat end of slot 373.

It was previously mentioned that U. H. F. panels 220 i bridge discs 341and 342' to form the U. H. F. turret 340.

Panels 220 (see Figures 8, 9 10 and 11) are formed of a dielectric base379. Dielectric'base 379 maybe a plastic molding provided with two slots378 and 386 and embossings 385 and 387. The end of base 220 opposite tothat in which slot 37S is located is provided with an `extension 345consisting of a head 382 and a,

neck 381. In the back of head 382 are the two shoulders 383. The moldedbase 379 is also provided with positioning stop 260 at one end of base379. Molded base 379 is provided with the U. H. F. contacts 223 226,229, 235 and 237 extending through the thickness of base- 379.cylindrical support 622 in the present embodiment made of an`appropriate ceramic such as steatite. The con-v ductive plates 221,225, 228, 233 and 236 are shaped (see especially Figures l0 and 11) sothat one portion of Molded base 379 is shaped to receive dielectricthese plates surrounds through a certain angular range the cylindricalsupport 622.

To be more specific, portion 624 of these conductive plates iscircularly shaped and provided with an opengroundrbetween plate 236 ofcapacitor`232idand adjusting :screw 348.. Y

The adiung We .348 engagamdufivedisc. 3.41,

through rslot `386. Extensions 4400 and `401 are appropriate'lyshapedv'to :give the-desired value of capacitance during the angular rotationof tine tuning .dielectric plate 270 with respect lto theplates 400 and*401. In addition, one or `more ofthe conductive plates, in this case225, is provided near its 'mounting endfwith radial extensions 630 and631 which rest against `appropriate embossings 632 and'633 obtained frommolding 379V and since the conductive plates are rigidly secured vtocylindrical support 622 and` `one of the plates in this case plate-225is provided with means which cooperate with lbosses 632 and 633, thusmaking it impossible `for plate 225, and therefore, for the wholeassembly to rotate with respect to panel '379. In other words, byappropriately shaping molding 379 and providing atleast one of theplates mounted on cylinder 622 with radial extensions, it becomespossible to restrict `,assembly r622, 221, 225,228, 233 and 236 fromrotational 'movements with respect to p1ate 379. Y f

rIl? then, the conductive plates are appropriately positioncd withrespect to the above-mentioned end 'of ceramic cylinder 622, they willalso be properly positioned withy respect to the dielectric plates 267,268, 269 and To firmly secure the conductive plate assembly to base 379,a clip 640 of resilient material is made to engage slots 385 and 387 toretain ceramic cylinder 622 against motion away from base 379. This typeof U. H. F. panel 220 considerably simplifies the Ymanufacturing ofthese panels sinceit makes possible the preparation of molded base 379separately from the conductive plates. Bases 379 are in fact, equal forall the U. H. F. panels 220.

When panels 220 are mounted on thesupporting discs 341 and 342, opening378 is engaged by ngers 365.so that the heads 366 of lingers 365 extendoutwardly from turret 340 through opening 378. Also extending outwardlyis the extension 390 and the capacitor plate ex-` tensions 400 'and 401.

Extension 345, or better its neck 381, is introduced in slot 344 of disc341 so that the shoulders 383 of extension 235 will be lbroughtagainstportion 358 of spring member 353 so that spring portion 358 will biaspanels 220 toward the front and-since the interior side of disc 341 isprovided with the small extension360, each panel 220 once mounted cannotbe removed through radial movement but must be lirst pressed against thebias of the spring porti-on 358and then moved from the vturret by radialmovement. Y

By this means, panels 220 are firmly secured to form turret 340. In theinterior of turret 340 and rigidly secured to shaft 310 are dielectricsleeves 406 and 407 carrying, respectively, dielectric plates 269, 268,and 267 of capacitors 232,231, and 222. Y

The front plate 341 of the U. H. F. turret 340, as previously mentioned,is secured toa `sleeve or hollow shaft 35') so that rotation of the samewill cause rotation of the U. H. F. turret 340. i

ln order to rigidly tie together discs 341, 342, a 4metallic bridge 410is provided (see Figure 7) approximately in the position determined bynotch 346 (Figure 13). This bar 410 is appropriately riveted such as at411 to plates 34?. and 341, also riveted through rivets 412 to anextension 413 ofshielding disc 391.

When notch 346 is engaged by the positioning device of the detent rolleras described hereinafter, then because or" the position of bar 410 theU. H. F. turret will become inoperative and only the V. H. F. sectionwill be operative so that it is possible to see now that notch 346corresponds with the position of V. H. F. reception alone. i

lt should also be noted that in order to'provide a really end (seeFigure 7) is appropriately bent so thatl it always Y bears against theinterior portion of shield 391 and thus provides a means for groundingthe shaft 310 at that point, shielding well one section of the U. H. F.tuner from the other and, therefore, improving the operation of the U.H. F. section.

It should also be noted that in order to position properly the structureconsisting of sleeves 406, 407 and the dielectric plates 267, 268 and269, the dielectric structure is biased toward the front by a U-shapedspring 415 secured to rear plate 342 in any appropriate way, forexample, by means of the previously mentioned rivet 411.

The positioning of dielectric elements 267, 268, 269 longitudinally onshaft 305 in turret 340 is quite important in that their position withrespect to the rotor mounted plates 233, 236, 221, 225 and 228 iscritical if the tuner is to operate at the desired frequencies.

The U. H. F. turret 340 when mounted as shown in Figure 2 will have theopening 344 or the notch 346 of supporting disc 341 in engagement withthe roller 417 mounted on a resilient finger 418. Finger 418 is rigidlysecured to chassis 305 through a screw 419, and a positioning extension423. Through the detent action provided by elernent 418 and roller 417over the outer surface of disc 341, it is possible to accuratelyposition contacts 223, 226, 229, 235, 237 and to accurately positionpanels 220 with respect to the stationary contacts of this U. H. F.turret. y

Stationary contacts N, P, Q, R, S are mounted by means of rivets 420 toa dielectric supporting bar 421 which is in turn secured through bracket422 to the chassis 305 of the present tuner. Mounted on the same bracket422 and secured to it in any appropriate way is the grounding contact392 for grounding shield 391 through its extension 390.

Secured to the front wall 425 of chassis 305 is an additional groundingcontact 426 which is continuously engaged by the outwardly extendingportions of conductive discs 341, thus providing a good ground for thedise 341 and, therefore, for the adjusting screws 348. Also mountedonthe chassis and in position so as to be complementary and cooperatingwith shield 391 is a conductive shield 427 which extends transversely inchassis 305 to also divide the oscillator section of the U. H. F. tunerVfrom the preselector section. y

By the lprovision of shielding means 391 and 427 it is possible toreduce considerably any oscillator radiation. When the tuner is mounted,the panel mounted contacts bear against the kidney spring contacts N toS and through cooperation of roller 417 with notches 344 or 346, therotary contacts will engage the stationary contacts N to S always at thedesired preselected position so as never to change the inductanee or theresistance of the path from the stationary contacts to the rotarycontacts.

This isV particularly important at ultra-high frequencies where anysmall shift of the contacts with respect to each other may producedetuning of the tuner.

VIn the foregoing the invention has been described solely in connectionwith specicillustrative embodiments thereof. now be obvious to thoseskilled in the art, it is preferred to be bound not by the specicdisclosures herein contained but only by therappended claims.

What is claimed is:

1. A panel for a turret tuner; said panel comprising an insulating base;a plurality of reactance components good grounding action and shieldingaction between the oscillator and `the preselectorV portion ofthe U. F.turret, a llat conductive spring member 414 is connected on one side(not shown) to ,the shaft v310, while its iiat supported on a surface ofsaid panel; a plurality of contact members carried on another surface ofsaid panel;

circuit connections between said reactance components Since manyvariations and modifications will tional means on said surface formaintaining the stator plates parallel to each other.

2. A panel for a turret tuner; said panel comprising an insulating base;a plurality of reactance components supported on a surface of saidpanel; a plurality of contact members carried on another surface of saidpanel; circuit connections between said reactance components and saidContact members; said panel also carrying a pluralityof stator plates ofa variable capacitor; said stator plates being secured to the surface ofthe panel to which the reactance components are secured, and additionalmeans on said surface for maintaining the stator plates parallel to eachother; said additional means comprising a cylindrical member secured tosaid surface; and a recess in each stator plate engaging saidcylindrical member; the plates extending in a plane normal to saidcylindrical member.

3. A panel for a turret tuner; said panel comprising an insulating base;a plurality of reactance components supported on a surface of saidpanel; a plurality of contact members carried on another surface of saidpanel; circuit connections between said reactance components and saidcontact members; said panel also carrying a plurality of stator platesof a variable capacitor; said stator plates being secured to the surfaceof the panel to which the reactance components are secured, andadditional means on said surface for maintaining the stator platesparallel to each other; said additional means comprising a cylindricalmember secured to said surface; vand a recess in each stator plateengaging said cylindrical member; the plates extending in a plane normalto said cylindrical member; said cylindrical member also furnishing a`support for at least certain of said reactance components. e

4. In a rotatable turret tuner, a plurality of panels eX- tendingparallel to the axis of said tuner, each panel comprising an insulatingbase; a plurality of reactance components supported on a surface of saidpanel; a plurality of contact members carried onanother surface of saidpanel; circuit connections between said reactance components and saidcontact members; said panel also carrying a plurality of stator platesof a variable capacitor and a plurality of rotor plates mounted on arotatable shaft; said rotatable shaft extending parallel to the axis ofthe turret and in a fixed position with respect thereto; the statorplates of each panel meshing with said rotor plates when the turret isrotated to bring said panel to a predetermined angular position.

5. In a rotatable turret tuner, a plurality of panels extending parallelto the axis of said tuner, each panel comprising an insulating base; aplurality of reactance components supported on a surface of said panel;a plurality of contact members carried on another surface of said panel;circuit connections between said reactance components and said contactmembers; said panel also carrying a plurality of stator plates of avariable capacitor and a plurality of rotor plates mounted on arotatable shaft; said rotatable shaft extending parallel to the axis ofthe turret and in a fixed position with respect thereto; the statorplates of each panel meshing with said rotor plates when the turret isrotated to bring said panel to a predetermined angular position, thestator plates of the particular panel which is moved to the angularposition 1'4 in which the stator plates of the panel mesh with the rotorplates forming at least one variable capacitor.

6. In a rotatable turret tuner, a plurality of panels extending parallelto the axis of said tuner, eachk panel comprising an insulating base; aplurality of reactance components supported on a surface of said panel;a plurality of contact members carrie on another surface of said panel;circuit connections between said reactance components and said contactmembers; said panel also carrying a plurality of stator plates of avariable capacitor and a plurality of rotor plates mounted on arotatable shaft; said rotatable shaft extending parallel to the axis ofthe turret land in a xed position with respect thereto; the statorplates of each panel meshing with said rotor plates when the turret isrotated to bring said panel to a predetermined angular position, thestator plates of the particular panel which is moved to the angularposition in which the stator plates of the panel mesh with the rotorplates forming yat least one variable capactitor, a plurality ofstationary contacts, the contact members of the panel which is locatedat a position for its stator plates to mesh with the rotor platesengaging the stationary contacts.

7. A panel for a turret tuner; said panel comprising `an insulatingbase; a plurality of reactance components supported on a surface of saidpanel; a plurality of contact members carried on another surface of saidpanel; circuit connections between said reactance components and saidcontact members; said panel also carrying a plurality of stator platesof a variable capacitor; said stator plates being secured to the surfaceof the panel to which the reactance 'components are secured, at leastone pair of adjacent stator plates extending through the panel andemerging on the opposite side thereof to form an additional pair ofstator plates. l

8. In la rotatable turret tuner, a plurality of panels extendingparallel to the axis of said tuner, each panelY to which the reactancecomponents are secured and a plurality of rotor plates mounted on arotatable shaft; said rotatable shaft extending parallel to the axis ofthe turret and in a fixed position with respect thereto;

the stator plates of each panel meshing with said rotor y plates whenthe turret is rotated to bring said panel'to a predetermined angularposition, at least one pair-of adjacent stator plates extending throughthe panel and emerging on the opposite side thereof to form anadditional pair of stator plates, and an additional line tuning rotorplate meshing with said extending stator plates.

References Cited in the tile of this patent UNITED STATES PATENTS1,664,685 Hudson Apr. 3, 1928 1,908,694 Danielson May 16, 1933 2,545,681Zepp et al Mar. 20, 1951 2,611,807

Lazzery Sept. 23, 1952

